WO2014087227A1 - Procédé et système pour démarrer et utiliser une alimentation en fil d'apport et une source d'énergie de forte intensité combinées en vue d'un soudage - Google Patents

Procédé et système pour démarrer et utiliser une alimentation en fil d'apport et une source d'énergie de forte intensité combinées en vue d'un soudage Download PDF

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Publication number
WO2014087227A1
WO2014087227A1 PCT/IB2013/002706 IB2013002706W WO2014087227A1 WO 2014087227 A1 WO2014087227 A1 WO 2014087227A1 IB 2013002706 W IB2013002706 W IB 2013002706W WO 2014087227 A1 WO2014087227 A1 WO 2014087227A1
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WO
WIPO (PCT)
Prior art keywords
wire
weld
filler wire
welding
puddle
Prior art date
Application number
PCT/IB2013/002706
Other languages
English (en)
Inventor
Steven R. PETER
Michael D. LATESSA
Paul Edward Denney
Original Assignee
Lincoln Global, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US13/706,581 external-priority patent/US20130092667A1/en
Application filed by Lincoln Global, Inc. filed Critical Lincoln Global, Inc.
Priority to JP2015600108U priority Critical patent/JP3201246U/ja
Priority to CN201380063190.5A priority patent/CN104822484A/zh
Priority to DE212013000247.5U priority patent/DE212013000247U1/de
Publication of WO2014087227A1 publication Critical patent/WO2014087227A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/21—Bonding by welding
    • B23K26/24—Seam welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/067—Dividing the beam into multiple beams, e.g. multifocusing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/32—Bonding taking account of the properties of the material involved
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26

Definitions

  • U.S. Patent Application Nos. 13/212,025 and 12/352,667 are incorporated herein by reference in their entirety.
  • the invention is related to a method of welding according to claim 1 and to a welding system according to claim 10.
  • Certain embodiments relate to filler wire overlaying applications as well as welding and joining applications. More particularly, certain embodiments relate to a system and method to start and use a combination filler wire feed and energy source system for any of brazing, cladding, building up, filling, hard-facing overlaying, joining and welding applications.
  • GTAW trench filler wire method
  • the filler wire which leads a torch, is resistance- heated by a separate power supply.
  • the wire is fed through a contact tube toward a work- piece and extends beyond the tube.
  • the extension is resistance-heated such that the extension approaches or reaches the melting point and contacts the weld puddle.
  • a tungsten electrode may be used to heat and melt the workpiece to form the weld puddle.
  • the power supply provides a large portion of the energy needed to resistance-melt the filler wire.
  • the wire feed may slip or faulter and the current in the wire may cause an arc to occur between the tip of the wire and the workpiece.
  • the extra heat of such an arc may cause burnthrough and spatter.
  • the risk of such an arc occurring is greater at the start of the process where the wire initially comes in contact with the workpiece at a small point. If the initial current in the wire is too high, the point may burn away, causing an arc to occur.
  • Embodiments of the present invention comprise a system and method to start and use a combination filler wire feeder and energy source system.
  • a first embodiment of the present invention comprises a method to start and use a combination wire feed and energy source system for any of brazing, cladding, building up, filling, hard-facing overlaying, welding and joining applications.
  • the method includes applying a sensing voltage between at least one resistive filler wire and a workpiece via a power source and advancing a distal end of the at least one resistive filler wire toward the workpiece.
  • the method further includes sensing when the distal end of the at least one resistive filler wire first makes contact with the workpiece.
  • the method also includes turning off the power source to the at least one resistive filler wire over a defined time interval in response to the sensing.
  • the method further includes turning on the power source at an end of the defined time interval to apply a flow of heating current through the at least one resistive filler wire.
  • the method also includes applying energy from a high intensity energy source to the workpiece to heat the workpiece at least while applying the flow of heating current.
  • the high intensity energy source may include at least one of a laser device, a plasma arc welding (PAW) device, a gas tungsten arc welding (GTAW) device, a gas metal arc welding (GMAW) device, a flux cored arc welding (FCAW) device, and a submerged arc welding (SAW) device.
  • PAW plasma arc welding
  • GTAW gas tungsten arc welding
  • GMAW gas metal arc welding
  • FCAW flux cored arc welding
  • SAW submerged arc welding
  • FIG. 1 illustrates a functional schematic block diagram of an exemplary embodiment of a combination filler wire feeder and energy source system for any of brazing, cladding, building up, filling, and hard-facing overlaying applications;
  • FIG. 3 illustrates a flow chart of an embodiment of a post start-up method used by the system of FIG. 1 ;
  • FIG. 4 illustrates a first exemplary embodiment of a pair of voltage and current waveforms associated with the post start-up method of FIG. 3;
  • FIG. 5 illustrates a second exemplary embodiment of a pair of voltage and current waveforms associated with the post start-up method of FIG. 3;
  • FIGs. 6 and 6A illustrate a further exemplary embodiment of the present invention used to perform a welding operation
  • FIGs. 7, 7A, and 7B illustrate additional exemplary embodiments of welding with the present invention
  • FIG. 8 illustrates a further exemplary embodiment of joining two sides of a joint at the same time
  • FIGs. 11A to 11C depict exemplary embodiments of contact tips used with embodiments of the present invention.
  • FIG. 12 illustrates a hot wire power supply system in accordance with an embodiment of the present invention
  • FIGs. 13A-C illustrate voltage and current waveforms created by exemplary embodiments of the present invention
  • FIG. 14 illustrates another welding system in accordance an exemplary embodiment of the present invention
  • FIG. 15 illustrates an exemplary embodiment of a weld puddle created by an embodiment of the present invention
  • FIG. 19 illustrates an exemplary embodiment of a fume extraction nozzle in accordance with the present invention
  • FIG. 20A illustrates results of a thin-wall welding process using an arc welding process
  • the system 100 also includes a hot filler wire feeder subsystem capable of providing at least one resistive filler wire 140 to make contact with the workpiece 115 in the vicinity of the laser beam 110.
  • a hot filler wire feeder subsystem capable of providing at least one resistive filler wire 140 to make contact with the workpiece 115 in the vicinity of the laser beam 110.
  • the hot filler wire feeder subsystem includes a filler wire feeder 150, a contact tube 160, and a hot wire power supply 170.
  • the filler wire 140 which leads the laser beam 110, is resistance-heated by electrical current from the hot wire welding power supply 170 which is operatively connected between the contact tube 160 and the workpiece 115.
  • the feeder subsystem may be capable of simultaneously providing one or more wires, in accordance with certain other embodiments of the present invention.
  • a first wire may be used for hard-facing and/or providing corrosion resistance to the workpiece
  • a second wire may be used to add structure to the workpiece.
  • the system 100 further includes a motion control subsystem capable of moving the laser beam 110 (energy source) and the resistive filler wire 140 in a same direction 125 along the workpiece 115 (at least in a relative sense) such that the laser beam 110 and the resistive filler wire 140 remain in a fixed relation to each other.
  • the relative motion between the workpiece 115 and the laser/wire combination may be achieved by actually moving the workpiece 115 or by moving the laser device 120 and the hot wire feeder subsystem.
  • the motion control subsystem includes a motion controller 180 operatively connected to a robot 190. The motion controller 180 controls the motion of the robot 190.
  • the robot 190 is operatively connected (e.g., mechanically secured) to the workpiece 115 to move the workpiece 115 in the direction 125 such that the laser beam 110 and the wire 140 effectively travel along the workpiece 115.
  • the laser device 110 and the contact tube 160 may be integrated into a single head. The head may be moved along the workpiece 115 via a motion control subsystem operatively connected to the head.
  • a high intensity energy source/hot wire may be moved relative to a workpiece. If the workpiece is round, for example, the high intensity energy source/hot wire may be stationary and the workpiece may be rotated under the high intensity energy source/hot wire. Alternatively, a robot arm or linear tractor may move parallel to the round workpiece and, as the workpiece is rotated, the high intensity energy source/hot wire may move continuously or index once per revolution to, for example, overlay the surface of the round workpiece. If the workpiece is flat or at least not round, the workpiece may be moved under the high intensity energy source/hot wire as shown if FIG. 1. However, a robot arm or linear tractor or even a beam-mounted carriage may be used to move a high intensity energy source/hot wire head relative to the workpiece.
  • the system 100 further includes a sensing and current control subsystem
  • the sensing and current control subsystem 195 which is operatively connected to the workpiece 115 and the contact tube 160 (i.e., effectively connected to the output of the hot wire power supply 170) and is capable of measuring a potential difference (i.e., a voltage V) between and a current (I) through the workpiece 115 and the hot wire 140.
  • the sensing and current control subsystem 195 is capable of sensing when the resistive filler wire 140 is in contact with the workpiece 115 and is operatively connected to the hot wire power supply 170 to be further capable of controlling the flow of current through the resistive filler wire 140 in response to the sensing, as is described in more detail later herein.
  • the sensing and current controller 195 may be an integral part of the hot wire power supply 170.
  • step 230 sense when the distal end of the at least one resistive filler wire 140 first makes contact with the workpiece 115.
  • the sensing and current controller 195 may command the hot wire power supply 170 to provide a very low level of current (e.g., 3 to 5 amps) through the hot wire 140.
  • Such sensing may be accomplished by the sensing and current controller 195 measuring a potential difference of about zero volts (e.g., 0.4V) between the filler wire 140 (e.g., via the contact tube 160) and the workpiece 115.
  • a significant voltage level above zero volts may not exist between the filler wire 140 and the workpiece 115.
  • step 240 turn off the power source 170 to the at least one resistive filler wire 140 over a defined time interval (e.g., several milliseconds) in response to the sensing.
  • the sensing and current controller 195 may command the power source 170 to turn off.
  • step 250 turn on the power source 170 at an end of the defined time interval to apply a flow of heating current through the at least one resistive filler wire 140.
  • the sensing and current controller 195 may command the power source 170 to turn on.
  • step 260 apply energy from a high intensity energy source 110 to the workpiece 115 to heat the workpiece 115 at least while applying the flow of heating current.
  • the method 200 may include stopping the advancing of the wire 140 in response to the sensing, restarting the advancing (i.e., re-advancing) of the wire 140 at the end of the defined time interval, and verifying that the distal end of the filler wire 140 is still in contact with the workpiece 115 before applying the flow of heating current.
  • the sensing and current controller 195 may command the wire feeder 150 to stop feeding and command the system 100 to wait (e.g., several milliseconds).
  • the sensing and current controller 195 is operatively connected to the wire feeder 150 in order to command the wire feeder 150 to start and stop.
  • the sensing and current controller 195 may command the hot wire power supply 170 to apply the heating current to heat the wire 140 and to again feed the wire 140 toward the workpiece 1 5.
  • the system 100 may enter a post start-up mode of operation where the laser beam 110 and hot wire 140 are moved in relation to the workpiece 115 to perform one of a brazing application, a cladding application, a build-up application, a hard-facing application, or a welding/joining operation.
  • FIG. 3 illustrates a flow chart of an embodiment of a post start-up method 300 used by the system 100 of FIG. 1.
  • step 310 move a high intensity energy source (e.g., laser device 120) and at least one resistive filler wire 140 along a workpiece 115 such that the distal end of the at least one resistive filler wire 140 leads or coincides with the high intensity energy source (e.g., laser device 120) such that energy (e.g., laser beam 110) from the high intensity energy source (e.g., laser device 120) and/or the heated workpiece 115 (i.e., the workpiece 115 is heated by the laser beam 110) melts the distal end of the filler wire 140 onto the workpiece 115 as the at least one resistive filler wire 140 is fed toward the workpiece 115.
  • energy e.g., laser beam 110
  • the distal end of the wire 140 becomes highly molten due to heating, the distal end may begin to pinch off from the wire 140 onto the workpiece 115.
  • the potential difference or voltage increases because the cross section of the distal end of the wire decreases rapidly as it is pinching off. Therefore, by measuring such a rate of change, the system 100 may anticipate when the distal end is about to pinch off and lose contact with the workpiece 115. Also, if contact is fully lost, a potential difference (i.e., a voltage level) which is significantly greater than zero volts may be measured by the sensing and current controller 195.
  • step 330 turn off (or at least greatly reduce, for example, by 95%) the flow of heating current through the at least one resistive filler wire 140 in response to sensing that the distal end of the at least one resistive filler wire 140 is about to lose contact with the workpiece 115.
  • the sensing and current controller 195 determines that contact is about to be lost, the controller 195 commands the hot wire power supply 170 to shut off (or at least greatly reduce) the current supplied to the hot wire 140. In this way, the formation of an unwanted arc is avoided, preventing any undesired effects such as splatter or burn- through from occurring.
  • step 340 sense whenever the distal end of the at least one resistive filler wire 140 again makes contact with the workpiece 115 due to the wire 140 continuing to advance toward the workpiece 115.
  • sensing may be accomplished by the sensing and current controller 195 measuring a potential difference of about zero volts between the filler wire 140 (e.g., via the contact tube 160) and the workpiece 115.
  • the sensing and current controller 195 measuring a potential difference of about zero volts between the filler wire 140 (e.g., via the contact tube 160) and the workpiece 115.
  • step 350 re-apply the flow of heating current through the at least one resistive filler wire in response to sensing that the distal end of the at least one resistive filler wire again makes contact with the workpiece.
  • the sensing and current controller 195 may command the hot wire power supply 170 to re-apply the heating current to continue to heat the wire 140. This process may continue for the duration of the overlaying application.
  • FIG. 4 illustrates a first exemplary embodiment of a pair of voltage and current waveforms 410 and 420, respectively, associated with the post start-up method 300 of FIG. 3.
  • the voltage waveform 410 is measured by the sensing and current controller 195 between the contact tube 160 and the workpiece 115.
  • the current waveform 420 is measured by the sensing and current controller 195 through the wire 140 and work- piece 115.
  • the rate of change of the voltage waveform 410 (i.e., dv/dt) will exceed a predetermined threshold value, indicating that pinch off is about to occur (see the slope at point 411 of the waveform 410).
  • a rate of change of current through (di/dt), a rate of change of resistance between (dr/dt), or a rate of change of power through (dp/dt) the filler wire 140 and the workpiece 115 may instead be used to indicate that pinch off is about to occur.
  • rate of change premonition techniques are well known in the art.
  • the sensing and current controller 195 will command the hot wire power supply 170 to turn off (or at least greatly reduce) the flow of current through the wire 140.
  • the sensing and current controller 195 senses that the distal end of the filler wire 140 again makes good contact with the workpiece 115 after some time interval 430 (e.g., the voltage level drops back to about zero volts at point 412), the sensing and current controller 195 commands the hot wire power supply 170 to ramp up the flow of current (see ramp 425) through the resistive filler wire 140 toward a predetermined output current level 450.
  • the ramping up starts from a set point value 440. This process repeats as the energy source 120 and wire 140 move relative to the workpiece 115 and as the wire 140 advances towards the work- piece 115 due to the wire feeder 150.
  • FIG. 5 illustrates a second exemplary embodiment of a pair of voltage and current waveforms 510 and 520, respectively, associated with the post start-up method of FIG. 3.
  • the voltage waveform 510 is measured by the sensing and current controller 195 between the contact tube 160 and the workpiece 115.
  • the current waveform 520 is measured by the sensing and current controller 195 through the wire 140 and workpiece 115.
  • the rate of change of the voltage waveform 510 (i.e., dv/dt) will exceed a predetermined threshold value, indicating that pinch off is about to occur (see the slope at point 511 of the waveform 510).
  • a rate of change of current through (di/dt), a rate of change of resistance between (dr/dt), or a rate of change of power through (dp/dt) the filler wire 140 and the workpiece 115 may instead be used to indicate that pinch off is about to occur.
  • rate of change premonition techniques are well known in the art.
  • the sensing and current controller 195 will command the hot wire power supply 170 to turn off (or at least greatly reduce) the flow of current through the wire 140.
  • the sensing and current controller 195 senses that the distal end of the filler wire 140 again makes good contact with the workpiece 115 after some time interval 530 (e.g., the voltage level drops back to about zero volts at point 512)
  • the sensing and current controller 195 commands the hot wire power supply 170 to apply the flow of heating current (see heating current level 525) through the resistive filler wire 140.
  • This process repeats as the energy source 20 and wire 140 move relative to the workpiece 115 and as the wire 140 advances towards the workpiece 115 due to the wire feeder 150. In this manner, contact between the distal end of the wire 140 and the workpiece 115 is largely maintained and an arc is prevented from forming between the distal end of the wire 140 and the workpiece 115. Since the heating current is not being gradually ramped in this case, certain voltage readings may be ignored as being inadvertent or faulty due to the inductance in the heating circuit.
  • a method and system to start and use a combination wire feed and energy source system for any of brazing, cladding, building up, filling, and hard-facing overlaying applications are disclosed.
  • High intensity energy is applied onto a workpiece to heat the workpiece.
  • One or more resistive filler wires are fed toward the workpiece at or just in front of the applied high intensity energy. Sensing of when a distal end of the one or more resistive filler wires makes contact with the workpiece at or near the applied high intensity energy is accomplished.
  • Electric heating current to the one or more resistive filler wires is controlled based on whether or not the distal end of the one or more resistive filler wires is in contact with the workpiece.
  • the applied high intensity energy and the one or more resistive filler wires are moved in a same direction along the workpiece in a fixed relation to each other.
  • systems and methods of the present invention are employed for welding or joining operations.
  • the embodiments discussed above have focused on the use of filler metals in overlaying operations.
  • aspects of the present invention can be used in welding and joining applications in which work- pieces are joined using welding operations and the use of a filler metal.
  • the above described embodiments, systems and methods are similar to that employed in welding operations, described more fully below. Therefore, in the following discussions it is understood that the discussions above generally apply, unless otherwise stated. Further, the following discussion may include reference to Figures 1 through 5.
  • welding/joining operations typically join multiple workpieces together in a welding operation where a filler metal is combined with at least some of the workpiece metal to form a joint. Because of the desire to increase production throughput in welding operations, there is a constant need for faster welding operations, which do not result in welds which have a substandard quality. Furthermore, there is a need to provide systems which can weld quickly under adverse environmental conditions, such as in remote work sites. As described below, exemplary embodiments of the present invention provide significant advantages over existing welding technologies.
  • coatings which can cause similar issues include, but are not limited to: paint, stamping lubricants, glass linings, aluminized coatings, surface heat treatment, nitriding or carbonizing treatments, cladding treatments, or other vaporizing coatings or materials. Exemplary embodiments of the present invention eliminate these issues, as explained below.
  • FIG. 6A a representative welding lap joint is shown.
  • two coated (e.g., galvanized) workpieces W1 W2 are to be joined with a lap weld.
  • the lap joint surfaces 601 and 603 are initially covered with the coating as well as the surface 605 of workpiece W1.
  • portions of the covered surface 605 are made molten. This is because of the typical depth of penetration of a standard welding operation. Because the surface 605 is melted the coating on the surface 605 is vaporized, but because of the distance of the surface 605 from the surface of the weld pool is large, the gases can be trapped as the weld pool solidifies. With embodiments of the present invention this does not occur.
  • the filler wire 140 is preheated to at or near its melting point its presence in the weld puddle will not appreciably cool or solidify the puddle and is quickly consumed into the weld puddle.
  • the general operation and control of the filler wire 140 is as described previously with respect to the overlaying embodiments.
  • the laser beam 110 can be precisely focused and directed to the surfaces 601/603, the depth of penetration for the pools 601 A/603 A can be precisely controlled. By controlling this depth carefully, embodiments of the present invention prevent any unnecessary penetration or melting of the surface 605. Because of the surface 605 is not overly melted any coating on the surface 605 is not vaporized and does not become trapped in the weld puddle. Further, any coating on the surface of the weld joint 601 and 603 are easily vaporized by the laser beam 110 and that gas is allowed to escape the weld zone before the weld puddle solidifies. It is contemplated that a gas extraction system can be utilized to aid in the removal of any vaporized coating materials.
  • the speed of welding coated workpieces can be greatly increased, while significantly mini- mizing or eliminating porosity.
  • Some arc welding system can achieve good travel speeds for welding, but at the higher speeds problems can occur such as porosity and spatter.
  • very high travel speeds can be achieved with little or no porosity or spatter (as discussed herein) and in fact travel speeds of over 50 inches/min can be easily achieved for many different types of welding operations.
  • Embodiments of the present invention can achieve welding travel speeds over 80 inches/minute. Further, other embodiments can achieve travel speeds in the range of 100 to 150 inches/min with minimal or no porosity or spatter, as discussed herein.
  • the speeds achieved will be a function of the workpiece properties (thickness and composition) and the wire properties (e.g., dia.), but these speeds are readily achievable in many different welding and joining applications when using embodiments of the present invention. Further, these speeds can be achieved with either a 100 % carbon dioxide shielding gas, or can be achieved with no shielding at all. Additionally, these travel speeds can be achieved without removing any surface coating prior to the creation of the weld puddle and welding. Of course, it is contemplated that higher travel speeds can be achieved. Furthermore, because of the reduced heat input into the weld these high speeds can be achieved in thinner workpieces 115, which typically have a slower weld speed because heat input must be kept low to avoid distortion.
  • embodiments of the present invention achieve the above described high travel speeds with little or no porosity or spatter, but they can also achieve very high deposition rates, with low admixture.
  • embodiments of the present invention can achieve deposition rates of 10 Ib/hr or higher with no shielding gas and little or no porosity or spatter. In some embodiments the deposition rate is in the. range of 10 to 20 Ib/hr.
  • these extremely high travel speeds are achieved with little or no porosity and little or no spatter.
  • Porosity of a weld can be determined by examining a cross-section and/or a length of the weld bead to identify porosity ratios.
  • the cross-section porosity ratio is the total area of porosity in a given cross-section over the total cross-sectional area of the weld joint at that point.
  • the length porosity ratio is the total accumulated length of pores in a given unit length of weld joint.
  • Embodiments of the present invention can achieve the above described travel speeds with a cross-sectional porosity between 0 and 20%.
  • a weld bead with no bubbles or cavities will have a 0% porosity.
  • the cross- sectional porosity can be in the range of 0 to 10%, and in another exemplary embodiment can be in the range of 2 to 5%. It is understood that in some welding applications some level of porosity is acceptable.
  • the length porosity of the weld is in the range of 0 to 20%, and can be 0 to 10%.
  • the length porosity ratio is in the range of 1 to 5%.
  • welds can be produced that have a cross-sectional porosity in the range of 2 to 5% and a length porosity ratio of 1 to 5%.
  • embodiments of the present invention can weld at the above identified travel speeds with little or no spatter.
  • Spatter occurs when droplets of the weld puddle are caused to spatter outside of the weld zone.
  • weld spatter occurs it can compromise the quality of the weld and can cause production delays as it must be typically cleaned off of the workpieces after the welding process. Thus, there is great benefit to welding at high speed with no spatter.
  • Embodiments of the present invention are capable of welding at the above high travel speeds with a spatter factor in the range of 0 to 0.5, where the spatter factor is the weight of the spatter over a given travel distance X (in mg) over the weight of the consumed filler wire 140 over the same distance X (in Kg). That is:
  • Spatter Factor (spatter weight (mg)/consumed filler wire weight (Kg))
  • the distance X should be a distance allowing for a representative sampling of the weld joint. That is, if the distance X is too short, e.g., 0.5 inch, it may not be representative of the weld. Thus, a weld joint with a spatter factor of 0 would have no spatter for the consumed filler wire over the distance X, and a weld with a spatter of factor of 2.5 had 5 mg of spatter for 2 Kg of consumed filler wire.
  • the spatter factor is in the range of 0 to 1. In a further exemplary embodiment, the spatter factor is in the range of 0 to 0.5.
  • the spatter factor is in the range of 0 to .3. It should be noted that embodiments of the present invention can achieve the above described spatter factor ranges with or without the use of any external shielding - which includes either shielding gas or flux shielding. Furthermore, the above spatter factor ranges can be achieved when welding uncoated or coated workpieces, including workpieces which are galvanized - without having the galvanization removed prior to the welding operation.
  • One method can include the use of a "spatter boat.”
  • a representative weld sample is placed in a container with a sufficient size to capture all, or almost all, of the spatter generated by a weld bead.
  • the container or portions of the container - such as the top - can move with the weld process to ensure that the spatter is captured.
  • the boat is made from copper so the spatter does not stick to the surfaces.
  • the representative weld is performed above the bottom of the container such that any spatter created during the weld will fall into the container. During the weld the amount of consumed filler wire is monitored.
  • the spatter boat is to be weighed by a device having sufficient accuracy to determine the difference, if any, between the pre-weld and post-weld weight of the container. This difference represents the weight of the spatter and is then divided by the amount, in Kg, of the consumed filler wire. Alternatively, if the spatter does not stick to the boat the spatter can be removed and weighed by itself.
  • the use of the laser device 120 allows for precise control of the depth of the weld puddle. Furthermore, the use of the laser 120 permits easy adjustment of the size and depth of the weld puddle. This is because the laser beam 110 can be focused/de-focused easily or have its beam intensity changed very easily. Because of these abilities the heat distribution on the workpieces W1 and W2 can be precisely controlled. This control allows for the creation of very narrow weld puddles for precise welding as well as minimizing the size of the weld zone on the workpiece. This also provides advantages in minimizing the areas of the workpiece that are not affected by the weld bead. Specifically, the areas of the workpieces adjacent to the weld bead will have minimal affects from the welding operation, which is often not the case in arc welding operations.
  • the shape and/or intensity of the beam 110 can be adjusted/changed during the welding process. For example, it may be necessary at certain places on a workpiece to change the depth of penetration or to change the size of the weld bead. In such embodiments the shape, intensity, and/or size of the beam 110 can be adjusted during the welding process to provide the needed change in the welding parameters.
  • the filler wire 140 impacts the same weld puddle as the laser beam 110.
  • the filler wire 140 impacts the weld puddle at the same location as the laser beam 110.
  • the filler wire 140 can impact the same weld puddle remotely from the laser beam.
  • the filler wire 140 trails the beam 110 during the welding operation.
  • the filler wire 140 can be positioned in the leading position.
  • the present invention is not limited in this regard, as the filler wire 140 can be positioned at other positions relative to the beam 110 so long as the filler wire 140 impacts the same weld puddle as the beam 110.
  • exemplary embodiments of the present invention are not limited to welding steel workpieces, but can also be used for welding aluminum, or more complex metals - as will be described further below.
  • Another beneficial aspect of the present invention is related to shielding gas.
  • shielding is provided by the use of externally supplied shielding gas, shielding gas created by the consumption of an electrode having flux on it (e.g., stick electrode, flux cored electrode, etc.) or by an externally supplied granulated flux (e.g., sub-arc welding).
  • shielding gas created by the consumption of an electrode having flux on it (e.g., stick electrode, flux cored electrode, etc.) or by an externally supplied granulated flux (e.g., sub-arc welding).
  • a special shielding gas mixture must be employed. Such mixtures can be extremely expensive.
  • the laser beam 110 can be focused very carefully to significantly reduce the overall heat input into the weld zone and thus significantly reduce the size of the weld puddle. Because the weld puddle is smaller the weld puddle cools much quicker. As such, there is no need for a trailing shielding gas, but only shielding at the weld. Further, for the similar reasons discussed above the spatter factor when welding titanium is greatly reduced while the rate of welding is increased.
  • two laser beams 110 and 110A are utilized - in line with each other - to create a unique weld profile.
  • a first beam 110 (emitted from a first laser device 120) is used to create first portion of a weld puddle 901 having a first cross-sectional area and depth
  • the second beam 110A (emitted from a second laser device - not shown) is used to create a second portion of a weld puddle 903 having a second cross-sectional area and depth, which is different from the first.
  • This embodiment can be used when it is desirable to have a portion of the weld bead having a deeper depth of penetration than the remainder of the weld bead. For example, as shown in FIG.
  • the puddle 901 is made deeper and narrower than the weld puddle 903 which is made wider and shallower.
  • Such an embodiment can be used when a deep penetration level is needed where the work pieces meet but is not desired for the entire portion of the weld joint.
  • This welding operation can also be accomplished with a single laser device 120 where the beam 110 is oscillated between a first beam shape/density and a second beam shape/density to provide the desired weld puddle profile.
  • a single laser device 120 where the beam 110 is oscillated between a first beam shape/density and a second beam shape/density to provide the desired weld puddle profile.
  • a corrosion resistant coating on the workpieces (such as galvanization), is removed during the welding process.
  • the second beam 11 OA and laser can be used to add a corrosion resistant overlay 903, such as a cladding layer, on top of the joint 901.
  • FIG. 10 depicts an exemplary embodiment of this invention. Although a V- type joint is shown, the present invention is not limited in this regard.
  • the beam 1 0 can have a rectangular shape (such that it impacts both workpieces) but a first region of the beam will have a first energy density and a second region of the beam 110 will have a second energy density which is different than the first region, so each of the regions can appropriately melt the respective workpieces.
  • the beam 110 can have a first region with a high energy density to melt a steel workpiece while the second region will have a lower energy density to melt an aluminum workpiece.
  • a wire can be directed to the melted portion 1022 which will then be combined with the melted portion 1012 for formation of the weld joint.
  • a single wire it should be heated to a temperature to allow the wire to melt in the portion 1022/1012 into which it is being immersed.
  • the chemistry of the filler wires should be chosen to ensure that the wires can sufficiently bond with the metals being joined.
  • the composition of the filler wire(s) should be chosen such that it has a suitable melt temperature, which allows it to melt and be consumed in the weld puddle of the lower temperature weld puddle.
  • the chemistries of the multiple filler wires can be different to attain the proper weld chemistry. This is particularly the case when the two different workpieces have material compositions where minimal admixture will occur between the materials.
  • the lower temperature weld puddle is the aluminum weld puddle 1012, and as such the filler wire(s) 1030(A) are formulated so as to melt at a similar temperature so that they can be easily consumed in the puddle 1012.
  • the filler wires can be silicon bronze, nickel aluminum bronze or aluminum bronze based wire having a melting temperature similar to that of the workpiece.
  • the filler wire compositions should be chosen to match the desired mechanical and welding performance properties, while at the same time providing melting characteristics which are similar to that of the at least one of the workpieces to be welded.
  • Exemplary embodiments for joining/welding can be similar to that shown in Figure 1.
  • a hot wire power supply 170 is provided which provides a heating current to the filler wire 140.
  • the current pass from the contact tip 160 (which can be of any known construction) to the wire 140 and then into the workpiece.
  • This resistance heating current causes the wire 140 between the tip 160 and the workpiece to reach a temperature at or near the melting temperature of the filler wire 140 being employed.
  • the melting temperature of the filler wire 140 will vary depending on the size and chemistry of the wire 140. Accordingly, the desired temperature of the filler wire during welding will vary depending on the wire 140.
  • the desired operating temperature for the filler wire can be a data input into the welding system so that the desired wire temperature is maintained during welding. In any event, the temperature of the wire should be such that the wire is consumed into the weld puddle during the welding operation.
  • at least a portion of the filler wire 140 is solid as the wire enters the weld puddle. For example, at least 30% of the filler wire is solid as the filler wire enters the weld puddle.
  • the hot wire power supply 170 supplies a current which maintains at least a portion of the filler wire at a temperature at or above 75% of its melting temperature.
  • the temperature of the wire before it enters the puddle can be approximately 1 ,600 °F, whereas the wire has a melting temperature of about 2,000 °F.
  • the respective melting temperatures and desired operational temperatures will varying on at least the alloy, composition, diameter and feed rate of the filler wire.
  • the power supply 170 maintains a portion of the filler wire at a temperature at or above 90% of its melting temperature.
  • portions of the wire are maintained at a temperature of the wire which is at or above 95% of its melting temperature.
  • the wire 140 will have a temperature gradient from the point at which the heating current is imparted to the wire 140 and the puddle, where the temperature at the puddle is higher than that at the input point of the heating current. It is desirable to have the hottest temperature of the wire 140 at or near the point at which the wire enters the puddle to facilitate efficient melting of the wire 140. Thus, the temperature percentages stated above are to be measured on the wire at or near the point at which the wires enters the puddle.
  • the wire 140 By maintaining the filler wire 140 at a temperature close to or at its melting temperature the wire 140 is easily melted into or consumed into the weld puddle created by the heat source/laser 120. That is, the wire 140 is of a temperature which does not result in significantly quenching the weld puddle when the wire 140 makes contact with the puddle. Because of the high temperature of the wire 140 the wire melts quickly when it makes contact with the weld puddle. It is desirable to have the wire temperature such that the wire does not bottom out in the weld pool - make contact with the non-melted portion of the weld pool. Such contact can adversely affect the quality of the weld.
  • the complete melting of the wire 140 can be facilitated only by entry of the wire 140 into the puddle.
  • the wire 140 can be completely melted by a combination of the puddle and the laser beam 110 impacting on a portion of the wire 140.
  • the heating/melting of the wire 140 can be aided by the laser beam 110 such that the beam 110 contributes to the heating of the wire 140.
  • the wire 140 and beam 110 intersect at the point at which the wire 140 enters the puddle.
  • the power supply 170 and the controller 195 control the heating current to the wire 140 such that, during welding, the wire 140 maintains contact with the workpiece and no arc is generated.
  • the presence of an arc when welding with embodiments of the present invention can result in significant weld deficiencies.
  • the voltage between the wire 140 and the weld puddle should be main- tained at or near 0 volts - which indicates that the wire is shorted to or in contact with the workpiece/weld puddle.
  • the power supply 170 monitors the voltage and as the voltage reaches or approaches a voltage value at some point above 0 volts the power supply 170 stops flowing current to the wire 140 to ensure that no arc is created.
  • the voltage threshold level will typically vary, at least in part, due to the type of welding electrode 140 being used.
  • the threshold voltage level is at or below 6 volts. In another exemplary embodiment, the threshold level is at or below 9 volts. In a further exemplary embodiment, the threshold level is at or below 14 volts, and in an additional exemplary embodiment; the threshold level is at or below 16 volts.
  • the threshold level for voltage will be of the lower type, while filler wires which are for stainless steel welding can handle the higher voltage before an arc is created.
  • the voltage is maintained in an operational range.
  • the voltage can be maintained in a range of 1 to 16 volts.
  • the voltage is maintained in a range of 6 to 9 volts.
  • the voltage can be maintained between 2 and 16 volts.
  • the power supply 170 contains circuitry which is utilized to monitor and maintain the voltage as described above.
  • circuitry which is utilized to monitor and maintain the voltage as described above.
  • the construction of such type of circuitry is known to those in the industry.
  • circuitry has been utilized to maintain voltage above a certain threshold for arc welding.
  • the heating current can also be monitored and/or regulated by the power supply 170. This can be done in addition to monitoring voltage, power, or some level of a voltage/amperage characteristic as an alternative. That is, the current can be maintained at a desired level or levels to ensure that the wire 140 is maintained at an appropriate temperature - for proper consumption in the weld puddle, but yet below an arc generation current level. For example, in such an embodiment the voltage and/or the current are being monitored to ensure that either one or both are within a specified range or below a desired threshold. The power supply then regulates the current supplied to ensure that no arc is created but the desired operational parameters are maintained.
  • the heating power (V x I) can also be monitored and regulated by the power supply 170. Specifically, in such embodiments the voltage and current for the heating power is monitored to be maintained at a desired level, or in a desired range. Thus, the power supply not only regulates the voltage or current to the wire, but can regulate both the current and the voltage. Such an embodiment may provide improved control over the welding system. In such embodiments the heating power to the wire can be set to an upper threshold level or an optimal operational range such that the power is to be maintained either below the threshold level or within the desired range (similar to that discussed above regarding the voltage).
  • the power supply 170 contains circuits which monitor the rate of change of the heating voltage (dv/dt), current (di/dt), and or power (dp/dt). Such circuits are often called premonition circuits and their general construction is known. In such embodiments, the rate of change of the voltage, current and/or power is monitored such that if the rate of change exceeds a certain threshold the heating current to the wire 140 is turned off.
  • the change of resistance (dr/dt) is also monitored.
  • the resistance in the wire between the contact tip and the puddle is monitored.
  • the output of the power supply is turned off as described herein to ensure an arc is not created.
  • Embodiments regulate the voltage, current, or both, to ensure that the resistance in the wire is maintained at a desired level.
  • the output of the power supply 170 is controlled such that no substantial arc is created during the welding operation.
  • the power supply can be controlled such that no substantial arc is created between the filler wire 140 and the puddle. It is generally known that an arc is created between a physical gap between the distal end of the filler wire 140 and the weld puddle. As described above, exemplary embodiments of the present invention prevent this arc from being created by keeping the filler wire 140 in contact with the puddle. However, in some exemplary embodiments the presence of an insubstantial arc will not compromise the quality of the weld.
  • the creation of an insubstantial arc of a short duration will not result in a level of heat input that will compromise the weld quality.
  • the welding system and power supply is controlled and operated as described herein with respect to avoiding an arc completely, but the power supply 170 is controlled such that to the extent an arc is created the arc is insubstantial.
  • the power supply 170 is operated such that a created arc has a duration of less than 10 ms.
  • the arc has a duration of less than 1 ms, and in other exemplary embodiments the arc has a duration of less than 300 s.
  • the filler wire 140 is desired to be in a constantly shorted state (in constant contact with the weld puddle) the current tends to decay at a slow rate. This is because of the inductance present in the power supply, welding cables and workpiece. In some applications, it may be necessary to force the current to decay at a faster rate such that the current in the wire is reduced at a high rate. Generally, the faster the current can be reduced the better control over the joining method will be achieved.
  • the ramp down time for the current after detection of a threshold being reached or exceeded, is 1 millisecond. In another exemplary embodiment of the present invention, the ramp down time for the current is 300 microseconds or less.
  • the ramp down time is in the range of 300 to 100 microseconds.
  • a ramp down circuit is introduced into the power supply 170 which aids in reducing the ramp down time when an arc is predicted or detected. For example, when an arc is either detected or predicted a ramp down circuit opens up which introduces resistance into the circuit.
  • the resistance can be of a type which reduces the flow of current to below 50 amps in 50 microseconds.
  • FIG 18. The circuit 1800 has a resistor 1801 and a switch 1803 placed into the welding circuit such that when the power supply is operating and providing current the switch 1803 is closed.
  • the above discussion can be further understood with reference to Figure 12, in which an exemplary welding system is depicted. (It should be noted that the laser system is not shown for clarity).
  • the system 1200 is shown having a hot wire power supply 1210 (which can be of a type similar to that shown as 70 in Figure 1 ).
  • the power supply 1210 can be of a known welding power supply construction, such as an inverter-type power supply. Because the design, operation and construction of such power supplies are known they will not be discussed in detail herein.
  • the power supply 1210 contains a user input 1220 which allows a user to input data including, but not limited to, wire feed speed, wire type, wire diameter, a desired power level, a desired wire temperature, voltage and/or current level.
  • the CPU/controller 1230 can determine the desired operational parameters in any number of ways, including using a lookup table, In such an embodiment, the CPU/controller 1230 utilizes the input data, for example, wire feed speed, wire diameter and wire type to determine the desired current level for the output (to appropriately heat the wire 140) and the threshold voltage or power level (or the acceptable operating range of voltage or power). This is because the needed current to heat the wire 140 to the appropriate temperature will be based on at least the input parameters. That is, an aluminum wire 140 may have a lower melting temperature than a mild steel electrode, and thus requires less current/power to melt the wire 140. Additionally, a smaller diameter wire 140 will require less current/power than a larger diameter electrode. Also, as the wire feed speed increases (and accordingly the deposition rate) the needed current/power level to melt the wire will be higher.
  • wire feed speed increases (and accordingly the deposition rate) the needed current/power level to melt the wire will be higher.
  • the input data will be used by the CPU/controller 1230 to determine the voltage/power thresholds and/or ranges (e.g., power, current, and/or voltage) for operation such that the creation of an arc is avoided.
  • the voltage/power thresholds and/or ranges e.g., power, current, and/or voltage
  • the CPU/controller 1230 determines the voltage/power thresholds and/or ranges (e.g., power, current, and/or voltage) for operation such that the creation of an arc is avoided.
  • the voltage/power thresholds and/or ranges e.g., power, current, and/or voltage
  • a positive terminal 1221 of the power supply 1210 is coupled to the contact tip 160 of the hot wire system and a negative terminal of the power supply is coupled to the workpiece W.
  • a heating current is supplied through the positive terminal 1221 to the wire 140 and returned through the negative terminal 1222.
  • a feedback sense lead 1223 is also coupled to the power supply 1210.
  • This feedback sense lead can monitor voltage and deliver the detected voltage to a voltage detection circuit 1240.
  • the voltage detection circuit 1240 communicates the detected voltage and/or detected voltage rate of change to the CPU/controller 1230 which controls the operation of the module 1250 accordingly. For example, if the voltage detected is below a desired operational range, the CPU/controller 1230 instructs the module 1250 to increase its output (current, voltage, and/or power) until the detected voltage is within the desired operational range. Similarly, if the detected voltage is at or above a desired threshold the CPU/controller 1230 instructs the module 1250 to shut off the flow of current to the tip 160 so that an arc is not created.
  • the CPU/controller 1230 instructs the module 1250 to supply a current or voltage, or both to continue the welding process.
  • the CPU/controller 1230 can also instruct the module 1250 to maintain or supply a desired power level.
  • the detection circuit 1240 and CPU/controller 1230 can have a similar construction and operation as the controller 195 shown in Figure 1.
  • the sampling/detection rate is at least 10 KHz.
  • the detection/sampling rate is in the range of 100 to 200 KHz.
  • Figures 13A-C depict exemplary current and voltage waveforms utilized in embodiments of the present invention. Each of these waveforms will be discussed in turn.
  • Figure 13A shows the voltage and current waveforms for an embodiment where the filler wire 140 touches the weld puddle after the power supply output is turned back on - after an arc detection event. As shown, the output voltage of the power supply was at some operational level below a determined threshold (9 volts) and then increases to this threshold during welding.
  • the operational level can be a determined level based on various input parameters (discussed previously) and can be a set operational voltage, current and/or power level. This operational level is the desired output of the power supply 170 for a given welding operation and is to provide the desired heating signal to the filler wire 140.
  • an event may occur which can lead to the creation of an arc.
  • the event causes an increase in the voltage, causing it to increase to point A.
  • the power supply/control circuitry hits the 9 volt threshold (which can be an arc detection point or simply a predetermined upper threshold, which can be below an arc creation point) and turns off the output of the power supply causing the current and voltage to drop to a reduced level at point B.
  • the slope of the current drop can be controlled by the inclusion of a ramp down circuit (as discussed herein) which aids in rapidly reducing the current resultant from the system inductance.
  • the current or voltage levels at point B can be predetermined or they can be reached after a predetermined duration in time.
  • an upper threshold for voltage (or current or power) set for welding not only is an upper threshold for voltage (or current or power) set for welding, but also a lower non-arc generation level.
  • This lower level can be either a lower voltage, current, or power level at which it is ensured that no arc can be created such that it is acceptable to turn back on the power supply and no arc will be created. Having such a lower level allows the power supply to turn back on quickly and ensure that no arc is created. For example, if a power supply set point for welding is set at 2,000 watts, with a voltage threshold of 11 volts, this lower power setting can be set at 500 watts.
  • the output is reduced to 500 watts.
  • This lower threshold can also be a lower current or voltage setting, or both, as well).
  • a timing circuit can be utilized to turn begin supplying current after a set duration of time. In exemplary embodiments of the present invention, such duration can be in the range of 500 to 1000 ms.
  • point C represents the time the output is again being supplied to the wire 140. It is noted that the delay shown between point B and C can be the result of an intentional delay or can simply be a result of system delay. At point C current is again being supplied to heat the filler wire.
  • the voltage increases while the current does not.
  • the wire makes contact with the puddle and the voltage and current settle back to the desired operational levels.
  • the voltage may exceed the upper threshold prior to contact at D, which can occur when the power source has an OCV level higher than that of the operating threshold.
  • this higher OCV level can be an upper limit set in the power supply as a result of its design or manufacture.
  • Figure 13B is similar to that described above, except that the filler wire 140 is contacting the weld puddle when the output of the power supply is increased. In such a situation either the wire never left the weld puddle or the wire was contacted with the weld puddle prior to point C.
  • Figure 13B shows points C and D together because the wire is in contact with the puddle when the output is turned back on. Thus both the current and voltage increase to the desired operational setting at point E.
  • Figure 14 depicts yet another exemplary embodiment of the present invention.
  • Figure 4 shows an embodiment similar to that as shown in Figure 1.
  • Figure 14 depicts a system 1400 in which a thermal sensor 1410 is utilized to monitor the temperature of the wire 140.
  • the thermal sensor 1410 can be of any known type capable of detecting the temperature of the wire 140.
  • the sensor 1410 can make contact with the wire 140 or can be coupled to the tip 160 so as to detect the temperature of the wire.
  • the sensor 1410 is a type which uses a laser or infrared beam which is capable of detecting the temperature of a small object - such as the diameter of a filler wire - without contacting the wire 140.
  • the senor 1410 is positioned such that the temperature of the wire 140 can be detected at the stick out of the wire 140 - that is at some point between the end of the tip 160 and the weld puddle.
  • the sensor 1410 should also be positioned such that the sensor 1410 for the wire 140 does not sense the weld puddle temperature.
  • the sensor 1410 is coupled to the sensing and control unit 195 (discussed with regard to Figure 1) such that temperature feed back information can be provided to the power supply 170 and/or the laser power supply 130 so that the control of the system 1400 can be optimized.
  • the power or current output of the power supply 170 can be adjusted based on at least the feedback from the sensor 1410. That is, in an embodiment of the present invention either the user can input a desired temperature setting (for a given weld and/or wire 140) or the sensing and control unit can set a desired temperature based on other user input data (wire feed speed, electrode type, etc.) and then the sensing and control unit 195 would control at least the power supply 170 to maintain that desired temperature.
  • the temperature of the wire 140 can be controlled only via power supply 170 by controlling the current in the wire 140.
  • at least some of the heating of the wire 140 can come from the laser beam 110 impinging on at least a part of the wire 140.
  • the current or power from the power supply 170 alone may not be representative of the temperature of the wire 140.
  • utilization of the sensor 1410 can aid in regulating the temperature of the wire 140 through control of the power supply 170 and/or the laser power supply 130.
  • the sensing and control unit 195 can be coupled to a feed force detection unit (not shown) which is coupled to the wire feeding mechanism (not shown - but see 150 in Figure 1).
  • the feed force detection units are known and detect the feed force being applied to the wire 140 as it is being fed to the workpiece 115.
  • a detection unit can monitor the torque being applied by a wire feeding motor in the wire feeder 150. If the wire 140 passes through the molten weld puddle without fully melting it will contact a solid portion of the workpiece and such contact will cause the feed force to increase as the motor is trying to maintain a set feed rate. This increase in force/torque can be detected and relayed to the control 195 which utilizes this information to adjust the voltage, current and/or power to the wire 140 to ensure proper melting of the wire 140 in the puddle.
  • the wire is not constantly fed into the weld puddle, but can be done so intermittently based on a desired weld profile.
  • the versatility of various embodiments of the present in- vention allows either an operator or the control unit 195 to start and stop feeding the wire 140 into the puddle as desired.
  • control unit 195 can operate only the laser 120 to cause a laser weld of this first portion of the joint, but when the welding operation reaches a second portion of the welding joint - which requires the use of a filler metal - the controller 195 causes the power supply and 170 and the wire feeder 150 to begin depositing the wire 140 into the weld puddle. Then, as the welding operation reaches the end of the second portion the deposition of the wire 140 can be stopped.
  • This allows for the creation of continuous welds having a profile which significantly varies from one portion to the next. Such capability allows a workpiece to be welded in a single welding operation as opposed to having many discrete welding operations. Of course, many variations can be implemented.
  • a weld can have three or more distinct portions requiring a weld profile with varying shape, depth and filler requirements such that the use of the laser and the wire 140 can be different in each weld portion.
  • additional wires can be added or removed as needed as well. That is, a first weld portion may need only a laser weld while a second portion only requires the use of a single filler wire 140, and a final portion of the weld requires the use of two or more filler wires.
  • the controller 195 can be made capable to control the various system components to achieve such a varying weld profile in a continuous welding operation, such that a continuous weld bead is created in a single weld pass.
  • Figure 15 depicts a typical weld puddle P when welding in accordance with exemplary embodiments of the present invention.
  • the laser beam 110 creates the puddle P in the surface of the workpiece W.
  • the weld puddle has a length L which is a function of the energy density, shape and movement of the beam 110.
  • the beam 110 is directed to the puddle P at a distance Z from the trailing edge of the weld puddle.
  • the high intensity energy source e.g., the laser 120
  • the high intensity energy source 120 does cause its energy to directly impinge on the filler wire 140 such that the energy source 120 does not melt the wire 140, rather the wire 140 completes its melting because of its contact with the weld puddle.
  • the trailing edge of the puddle P can be generally defined as the point at which the molten puddle ends and the weld bead WB created begins its solidification.
  • the distance Z is 50% of the length L of the puddle P. In a further exemplary embodiment, the distance Z is in the range of 40 to 75% the length L of the puddle P.
  • the filler wire 140 impacts the puddle P behind the beam 110 - in the travel direction of the weld - as shown in Figure 15. As shown the wire 140 impacts the puddle P as distance X before the trailing edge of the puddle P. In an exemplary embodiment, the distance X is in the range of 20 to 60% of the length of the puddle P. In another exemplary embodiment, the distance X is in the range of 30 to 45% of the length L of the puddle P. In other exemplary embodiments, the wire 140 and the beam 110 intersect at the surface of or at a point above the puddle P such that at least some of the beam 110 impinges on the wire 140 during the welding process.
  • the laser beam 110 is utilized to aid in the melting of the wire 140 for deposition in the puddle P.
  • Using the beam 110 to aid in the melting of the wire 140 aids in preventing the wire 140 from quenching the puddle P if the wire 140 is too cool to be quickly consumed in the puddle P.
  • the energy source 120 and beam 110 do not appreciably melt any portion of the filler wire 140 as the melting is completed by the heat of the weld puddle.
  • the wire 140 trails the beam 110 and is in line with the beam 110.
  • the present invention is not limited to this configuration as the wire 140 can lead (in the travel direction). Further, it is not necessary to have the wire 140 in line with the beam in the travel direction, but the wire can impinge the puddle from any direction so long as suitable wire melting occurs in the puddle.
  • Figures 16A through 16F depict various puddles P with the footprint of the laser beam 110 depicted. As shown, in some exemplary embodiments the puddle P has a circular footprint. However, embodiments of the invention are not limited to this configuration. For example, it is contemplated that the puddle can have elliptical or other shapes as well.
  • the laser beam 110 can remain stationary with respect to the weld puddle P. That is, the beam 110 remains in a relatively consistent position with respect to the puddle P during welding.
  • Figure 16A-16D depicts an embodiment where the beam 110 is translated in a circular pattern around the weld puddle P. In this figure the beam 110 translates such that at least one point on the beam 110 overlaps the center C of the puddle at all times. In another embodiment, a circular pattern is used but the beam 110 does not contact the center C.
  • Figure 16B depicts an embodiment where the beam is translated back-and-forth along a single line.
  • Figures 16E and 16F depict a cross-section of a workpiece W and puddle P using different beam intensities.
  • Figure 16E depicts a shallow wider puddle P which is created by a wider beam 110
  • Figure 16F depicts a deeper and narrow weld puddle P - typically referred to as a "keyhole”.
  • the beam is focused such that its focal point is near the upper surface of the workpiece W. With such a focus the beam 110 is able to penetrate through the full depth of the workpiece and aid in creating a back bead BB on the bottom surface of the workpiece W.
  • the beam intensity and shape are to be determined based on the desired properties of the weld puddle during welding.
  • FIG. 17 depicts a system 1700 in accordance with an exemplary embodiment of the present invention, where the laser 120 can be moved and have its optics (such as its lenses) changed or adjusted during operation.
  • This system 1700 couples the sensing and control unit 195 to both a motor 1710 and an optics drive unit 1720.
  • the motor 1710 moves or translates the laser 120 such that the position of the beam 110 relative to the weld puddle is moved during welding.
  • the motor 1710 can translate the beam 110 back and forth, move it in a circular pattern, etc.
  • the optics drive unit 1720 receives instructions from the sensing and control unit 195 to control the optics of the laser 120.
  • the optics drive unit 1720 can cause the focal point of the beam 110 to move or change relative to the surface of the workpiece, thus changing the penetration or depth of the weld puddle.
  • the optics drive unit 1720 can cause the optics of the laser 120 to change the shape of the beam 110.
  • the sensing and control unit 195 control the laser 120 and beam 110 to maintain and/or modify the properties of the weld puddle during operation.
  • hot wire laser welding that is consistent with the present invention allows for narrow gap welding that would have been difficult with arc-type or laser only welding processes.
  • the hot wire laser welding of the present invention allows for welding of thin- wall workpieces, e.g., less than 10 mm, that may not have been possible with traditional arc welding processes. This is especially true when the weld depth will be longer in length than the thickness of the material. For example, as shown in Figure 20A the joint depth is longer than the thicknesses of the respective workpieces 1 5A 115B.
  • the joint depth or weld bead depth is deeper (in length) than the thickness of at least one of the workpieces, and in other embodiments the bead is deeper than the thickness of both workpieces.
  • arc processes such as GMAW
  • arc processes need a wide gap in order to provide the shielding gas and to prevent the ferrous side walls of the weld groove from interfering with the arc as discussed above.
  • the heat input required to melt the excess filler material can distort thin-wall workpieces.
  • the weld puddle in an arc-type process can bridge a joint without penetrating deeply, which can lead to a stress riser in the finished joint.
  • the arc-type process can have a wide weld cap, which can make it difficult to determine the depth of the weld.
  • a visible heat line 116 on the workpiece 115B provides an indication of the depth of penetration of the weld puddle, i.e., an indication of the bottom of the weld joint.
  • the wide weld cap in a typical arc welding process such as a GMAW process, will cover the outer edge of a thin workpiece such as workpiece 115B.
  • the top outer edge of the workpiece corresponds to the top of the weld joint. Without knowing where the top outer edge of the workpiece 115B is (i.e., the top of the weld joint), it will be difficult to know the depth of penetration.
  • the laser only process has other disadvantages.
  • the laser in the laser only welding process, the laser is more focused than in a cladding-type process in order to provide the intensity to melt the workpiece and form a weld puddle.
  • the workpieces typically have to be fit very tightly, e.g., typically less than a 1 mm gap. Otherwise, the laser will shoot through the gap in the joint and/or the weld puddle formed by the laser will be unable to bridge the gap.
  • the gap GP will have an average gap width in the range of 1 to 3 times the diameter of the wire 140. In other exemplary embodiments, the average gap width will be in the range of 1 to 2 times the diameter of the wire 140. Generally, the average gap width refers to the average distance between the respective sidewalls of the joint for the depth of the joint. In exemplary embodiments of the present invention, the laser 120 and hot wire 140 will produce a weld puddle that is approximately two times the diameter of the hot wire 140.
  • processes of the present invention can have a penetration depth in the range of 4 to 10 times the diameter of the hot wire 140, while in other exemplary embodiments of the present the penetration can be in the range of 6 to 10 times the diameter of the hot wire 140.
  • penetration depth in the range of 4 to 10 times the diameter of the hot wire 140
  • the penetration can be in the range of 6 to 10 times the diameter of the hot wire 140.
  • the thicknesses of the workpieces can be relatively thin.
  • the workpieces 115A and 15B can have a thickness, at the weld joint, in the range of 4 to 15 mm, and in some embodiments can be in the range of 4 to 10 mm, without resulting in appreciable distortion.
  • Such a thickness would be the average thickness of the workpiece(s) at the weld joint for the depth of the weld joint, and may or may not be thickness for the entire length of the weld joint.
  • exemplary embodiments of the present invention can provide a weld joint having very narrow gap width, but deep penetration, which cannot be achieved by traditional welding operations.
  • the hot-wire laser process described above produces weld penetration that goes well into the root of the joint and forms a strong joint using less filler material and heat input than a typical arc-welding process.
  • the deposition rates and wire feed speeds are comparable to traditional arc welding processes. For example, it is contemplated that, based on the welding parameters, travel speeds greater than 100 ipm and wire feed speeds greater than 400 ipm can be achieved. Further, inspecting the weld is easier because the weld cap does not cover the top edge of the thin- wall workpiece 115B, as in an arc-type process. Because the top outer edge of workpiece 115B is visible, the distance between the top of the joint (top edge) and the bottom of the joint (heat line 116) can be easily measured.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Arc Welding In General (AREA)
  • Laser Beam Processing (AREA)

Abstract

L'invention porte sur un procédé et un système (100, 1200, 1400, 1700) pour souder ou assembler des pièces (115, 115A, 115B, W) mettant en oeuvre une source d'énergie de forte intensité afin de créer un bain de fusion (P) et au moins un fil d'apport résistif (140) qui est chauffé à sa température de fusion ou au voisinage de celle-ci et déposé dans le bain de fusion (P). Un circuit de surveillance sert à éviter la production d'arc entre le fil d'apport et les pièces.
PCT/IB2013/002706 2012-12-06 2013-12-06 Procédé et système pour démarrer et utiliser une alimentation en fil d'apport et une source d'énergie de forte intensité combinées en vue d'un soudage WO2014087227A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2015600108U JP3201246U (ja) 2012-12-06 2013-12-06 溶接のためにフィラーワイヤ送給装置と高強度エネルギー源との組み合せを開始及び使用するシステム
CN201380063190.5A CN104822484A (zh) 2012-12-06 2013-12-06 启动以及使用组合填充焊丝输送和高强度能量源的用于焊接的方法和系统
DE212013000247.5U DE212013000247U1 (de) 2012-12-06 2013-12-06 System zum Starten und Verwenden einer kombinierten Fülldrahtzufuhr- und Hochintensitäts-Energiequelle zum Schweissen

Applications Claiming Priority (2)

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US13/706,581 2012-12-06
US13/706,581 US20130092667A1 (en) 2009-01-13 2012-12-06 Method and System to Start and Use Combination Filler Wire Feed and High Intensity Energy Source for Welding

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WO2014087227A1 true WO2014087227A1 (fr) 2014-06-12

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JP (1) JP3201246U (fr)
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WO (1) WO2014087227A1 (fr)

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CN104400195A (zh) * 2014-10-30 2015-03-11 诸暨斯贝达机械有限公司 钨极气体保护焊接方法及应用
CN104439650A (zh) * 2014-12-12 2015-03-25 诸暨斯贝达机械有限公司 高效率焊接方法及应用
CN104607770A (zh) * 2014-12-12 2015-05-13 诸暨斯贝达机械有限公司 铜和钢的添丝焊接方法及应用
WO2016041064A1 (fr) * 2014-09-17 2016-03-24 Magna International Inc. Procédé de soudage au laser de feuilles d'acier revêtues avec l'ajout d'éléments d'alliage
US10052721B2 (en) 2014-09-17 2018-08-21 Magna International Inc. Method of laser welding coated steel sheets with addition of alloying elements
CN113798677A (zh) * 2021-09-14 2021-12-17 江苏科技大学 一种双相不锈钢与钛合金的焊接方法

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DE102018108824A1 (de) * 2018-04-13 2019-10-17 Rofin-Sinar Laser Gmbh Verfahren und Vorrichtung zum Laserschweißen
US11014185B2 (en) * 2018-09-27 2021-05-25 Illinois Tool Works Inc. Systems, methods, and apparatus for control of wire preheating in welding-type systems
KR102637807B1 (ko) * 2023-10-24 2024-02-16 유한회사 에스제이기공 원형 홈과 이면비드 공정을 활용한 강화 용접 시스템

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WO2016041064A1 (fr) * 2014-09-17 2016-03-24 Magna International Inc. Procédé de soudage au laser de feuilles d'acier revêtues avec l'ajout d'éléments d'alliage
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CN104439650A (zh) * 2014-12-12 2015-03-25 诸暨斯贝达机械有限公司 高效率焊接方法及应用
CN104607770A (zh) * 2014-12-12 2015-05-13 诸暨斯贝达机械有限公司 铜和钢的添丝焊接方法及应用
CN113798677A (zh) * 2021-09-14 2021-12-17 江苏科技大学 一种双相不锈钢与钛合金的焊接方法
CN113798677B (zh) * 2021-09-14 2024-02-27 江苏科技大学 一种双相不锈钢与钛合金的焊接方法

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DE212013000247U1 (de) 2015-10-09
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JP3201246U (ja) 2015-12-03

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